Lemoine is a surname of French origin, derived from the Old French word "le moin," which means "the monk." It was originally an occupational name for someone who worked at a monastery or had some association with monks. The name Lemoine has been prevalent in France since the Middle Ages and has since spread to other countries through emigration. Today, it is still predominantly found in France but can also be encountered in other parts of the world, particularly in Canada and the United States.
The name Lemoine experienced varied popularity throughout the period of 1917 to 1956, with peaks occurring between 1920 and 1928, and again in 1937. There were notably more births in these peak years compared to others, but overall, the name's popularity was consistent with around five births per year on average.